380 



MR. G. S. BRADY'S MONOGRAPH OF 



from which a single ridge runs forward, gradually merging in the flattened encircling 

 flange of the anterior border. Seen from the front, the shell is subquadrangular, the 

 sides convex, but flattened, the dorsum forming a flattened arch ; the ventral border 

 perfectly flat, and bounded by the projections of the outermost ventral ridges ; the inner 

 ridges form also conspicuous projections, which run obliquely upwards and inwards 

 towards the flattened anterior flange. Lucid spots about six, oblong and irregularly 

 placed, their long diameters pointing transversely across the valve. Surface of the shell 

 smooth and shining, marked by fine impressed lines, forming a pattern similar to the 

 imbrication of fish-scales. Colour pale greenish or white, transparent, with large and 

 irregularly spread patches of deep olive-green or black. 



Female. — Subquadrangular. Anterior border flattened, flanged, forming with the 

 ventral margin a well-marked angle; rounded above. Dorsal margin boldly arched, 

 highest at the posterior third, whence it sweeps round with a deep curve to the postero- 

 ventral angle. Ventral margin straight, slightly rising behind, and terminating in a 

 flattened squamous plate, which projects backwards, with the appearance of a spine. The 

 other aspects are similar to those of the male shell, except that the ventral surface of the 

 left valve has at the posterior extremity of its contact margin a flattened squamous 

 plate (fig. 66), which is received into a corresponding depression of the opposite valve. 



The mandibles have a structure similar to those of other Cyprida? ; but the branchial 

 appendage rises from ihe lower instead of the upper border of the palp* (Plate XXXYII. 

 fig. 3 c). The second pair of jaws have no branchial appendage. In the female (fig. 3e') 

 they possess a large subcorneal palp, which terminates in two setae. In the male they are 

 pediform ; the last joint of the right side (Hg. 3 e") is much elongated, and terminates in a 

 short seta and a long flexuous claw, which is composed of a strong midrib, with lateral 

 membranous expansions ; the left jaw has its last joint (fig. 3 e'") shorter and wider, its 

 inner margin having two strongly marked angles, one a little above the middle, the 

 other near the lower extremity ; the outer margin is flexuous, and is produced laterally 

 near its distal extremity into an acutely angular projection ; the terminal claw is 

 falciform : the penultimate joint of both sides bears at its apex a dense tuft of short 

 setse. The first foot in both sexes terminates in three curved claws, the central one 

 being much the strongest and longest (fig. 3/',/"). The second foot is slender and 

 curved upward, like that of Cypris, terminating in three equal setse, the second and 

 third joints also giving off each a long apical seta (fig. 3^). The " glandula mucosa," 

 or testis of the male, consists of a central cylinder, closely beset with radiating filaments 

 (fig. 2>l), arranged in 50-60 transverse rows, the whole organ being imbedded in a sort 

 of glairy matrix. The two glands are connected each by an efi'erent duct with the 

 " bursa copulatrix,''^ an organ of very complicated structure (fig. 3^), and consisting 

 essentially (so far as I can make out) of a much convoluted canal (? vesicula seminalis), an 

 intromittent organ or j^^nis, and two hooked appendages. The whole organ is very 

 dense in structure, consisting probably of chitine, deep brown in colour, and, with the 



* I at first thought that this appearance must arise from distortion, the parts of the animal having probably got 

 twisted during dissection aud manipulation under the microscope ; but in order to correct any error of this kind, I 

 fxanuiied several animals, aud always with the same result. 



